Chromatographic-Densitometric Analysis of Chosen Fluoroquinolones on TLC Plates Using Mobile Phases with Different Viscosity

Abstract

TLC-densitometric method was developed for the identification and quantitative determination of selected fluoroquinolones. Silica gel TLC 60 F₂₅₄ plates were used as the stationary phase. For the separation of examined compounds the suitability of the following four mobile phases with different dynamic viscosity was checked: (I) methanol:ammonia:ethyl acetate:acetonitrile 1:1:2:1 v/v/v/v (1.70 mPa · s), (II) dichloromethane:methanol:isopropanol:ammonia 4:4:5:2 v/v/v/v (2.08 mPa · s), (III) dichloromethane:ethanol:toluene:ammonia:n-butanol:water 6:6:2:1.8:3:0.3 v/v/v/v/v/v (2.27 mPa · s), (IV) 1,4- dioxane:ammonia:tetrahydrofuran 6:3:2 v/v/v (3.24 mPa · s). The calculated values of retardation factors R_F, capacity factors k, selectivity factors α, resolution factors R_s, and also asymmetry factors A_s for the evaluation of separation conditions were used. The obtained results confirmed that dynamic viscosity of the mobile phases is essential and influences the retention parameters of the studied fluoroquinolone chemotherapeutics. The validation results for the mobile phase IV indicate its suitability for the identification and also quantitative analysis of selected drugs in pharmaceutical analysis.

Keywords:

• densitometry
• determination
• fluoroquinolone antibiotics
• separation
• thin-layer chromatography

Acknowledgements

The authors would like to dedicate this article to the memory of Professor Jan Krzek, our adviser, mentor and Head of Department of Inorganic and Analytical Chemistry.